What happens to the material on the outside of a bend when bending metal?

When bending metal, the material on the outside of the bend experiences stretching. This occurs because, as the metal is bent, the outside fibers of the material must elongate to accommodate the new shape. When the bend radius decreases, the outer surface stretches more than the inner surface, which contracts. This differential movement results in the outer fibers being pulled apart, resulting in stretching of the material on that side.

The inner part of the bend, in contrast, is compressed, which is an important aspect of metalworking that affects how the final piece will perform in terms of strength and ductility. Understanding this behavior is crucial for applications in sheet metal fabrication and helps ensure that the bending process results in a structure that meets design specifications without compromising material integrity.